Ruixinia
Named in honor of Ruixin Zhang, who made significant contributions to the infrastructure and collection of the Erlianhaote Dinosaur Museum.
Ruixinia is an extinct genus of somphospondylan sauropod dinosaur from the Early Cretaceous (Barremian) Yixian Formation of China. The genus contains a single species, Ruixinia zhangi, known from a partial articulated skeleton. This specimen preserves the most complete series of caudal vertebrae known from any Asian titanosauriform.
Under dispute
Ruixinia was described as a somphospondylan, favored by its describers as a basal titanosaur (Mo and colleagues, 2023), but has been recovered within Euhelopodidae by Han and colleagues (2024).
Diagnosis
- Distinct foramina present at the anterodorsal corner of the pleurocoels of the mid-posterior dorsals
- Anterior caudal neural spines bifid
- Anterior caudal neural spines with projecting subtriangular processes on the anterior margins
- Distinct grooves present on the lateral surface of neural arches in Caudals 2-12
- Transition point present between Caudal 22 and Caudal 23 with size discontinuity
- Distalmost six caudals fused
- Chevron 18 with a bifurcated posterior process
- Chevron 20 approximately pentagonal in lateral view
- Chevrons 23-36 plank-shaped and unfused distally
- Lateral bulge developed on the lateral surface of the posterior lobe of the ilium
- Posterior margin of the tibial shaft strongly convex
Species
Ruixinia zhangi Mo et al., 2023
Type species
Named for Ruixin Zhang, a contributor to the Erlianhaote Dinosaur Museum, with the Latin genitive '-i' suffix indicating an honorific.
- Holotype
- ELDM EL-J009 , Erlianhaote Dinosaur Museum
- Material
- Articulated skeleton including cervicals, dorsals, sacrals, 52 caudals with 36 chevrons, dorsal ribs, left ilium, left pubis, left femur, left tibia, left astragalus, left metatarsal V, and left pedal phalanx
- Horizon
- Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
- Locality
- Batuyingzi, Beipiao, Liaoning, China
References
- Mo, J.; Ma, F.; Yu, Y.; Xu, X. (2023). A new titanosauriform sauropod with an unusual tail from the Lower Cretaceous of northeastern China. Cretaceous Research 144. Elsevier BV. doi:10.1016/j.cretres.2022.105449 mo2023b
-
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.
Source of the mass and hip height estimates.
jones2026b -
Han, F.; Yang, L.; Lou, F.; Sullivan, C.; Xu, X.; Qiu, W.; Liu, H.; Yu, J.; Wu, R.; Ke, Y.; Xu, M.; Hu, J.; Lu, P. (2024). A new titanosaurian sauropod, Gandititan cavocaudatus gen. et sp. nov., from the Late Cretaceous of southern China. Journal of Systematic Palaeontology 22(1): 2293038. Informa UK Limited. doi:10.1080/14772019.2023.2293038
Described Gandititan and recovered Ruixinia within Euhelopodidae in the phylogenetic analysis.
han2024a